1. Field of the Invention
The present invention relates, in general, to outside up-down elevators selectively installed on the outer walls of buildings and capable of being vertically movable along the outer walls and, more particularly, to a portable outside up-down elevator designed to be almost completely prevented from an unexpected quick movement, and smoothly raised without an initial downward movement when the outside up-down elevator is restarted in an ascending direction after it is temporarily stopped during an operation.
2. Description of the Prior Art
In a state of emergency, such as a fire, at a multistory building, residents use emergency facilities, such as emergency exits, outside up-down elevators or ladder trucks, in order to escape the emergency and avoid harmful results. However, both conventional outside up-down elevators and emergency exits are typically designed to be enclosed within walls and so they may fail to allow the residents to effectively avoid harmful results in such an emergency. On the other hand, conventional ladder trucks are problematic in that they may fail to effectively rescue the residents of higher stories due to the limited extension of their ladders. During a washing work for cleaning the outer walls of a multistory building, workers use specifically knotted ropes in order to repeatedly stop and descend along the outer walls while washing the outer walls. However, the knots of the ropes may be unexpectedly loosened and result in safety hazards. Another problem experienced in such ropes used in washing the outer walls of buildings is that the ropes do not allow workers to ascend along the outer walls.
In an effort to overcome the above problems, the applicant of this invention proposed a safety outside up-down elevator in Korean Patent Publication No. 95-4519. As shown in FIG. 1 of the accompanying drawings of this invention, the safety outside up-down elevator is designed to be motor-operated or manually operated so as to ascend or descend. The outside up-down elevator is also selectively stopped when there is an obstacle in an outside up-down elevator's moving passage while descending, and it is raised in order to avoid the obstacle.
As shown in the drawing, the safety outside up-down elevator comprises a planetary-type gear box, which is comprised of one sun gear 64, a plurality of planetary gears 66, 67, 68 and one internal gear 70. The three planetary gears 66 to 68 commonly and externally engage with the sun gear 64, while the internal gear 70 internally engages with the three planetary gears 66 to 68. A shaft 12 is rotatably coupled to the end plate 80 of the gear box, while the internal gear 70 is fixedly screwed to the end plate 80. A planetary gear carrier 65 is rotatably fitted over the shaft 12, with the top surface of the gear carrier 65 carrying the three planetary gears 66 to 68 and the bottom surface being concentrically integrated with a pulley 69. The pulley 69 has an annular groove on its outer surface, thus allowing a rope 11 to be wrapped around.
The sun gear 64 is set between the three planetary gears 66 to 68 so as to engage with the planetary gears 66 to 68. Fitted over the shaft 12 at a position just above the sun gear 64 is a flywheel 60, with a brake weight 63 being set in an arcuate groove 62 formed on the outer surface of the flywheel's rim 61. A cap-shaped cover 55 is fitted over the top of the flywheel 60, thus covering the flywheel 60.
The end plate 80 is provided with three rollers 76, 77 and 78, which guide the rope 11 to the pulley 69 and thereby allow the rope 11 to be wrapped around the pulley 69.
A brake band 50 is set in the cover 55, with one end of the band 50 being hinged to the cover 55 and the other end being connected to a lever 51. The above brake band 50 is brought into close contact with the outer surface of the flywheel 60. In order to elastically bias the brake band 50 to the outer surface of the flywheel 60, both the lever 51 and one spring 52 are coupled to a hinge 53. Due to the spring 52, the brake band 50 always comes into close contact with the outer surface of the flywheel 60. The lever 51 is selectively turned, thus releasing the flywheel 60 from the brake band 50 and allowing the flywheel 60 to be rotatable.
In the operation of the above safety outside up-down elevator, the outside up-down elevator descends under the weight of a user when the flywheel 60 is released from the brake band 50 by operating the lever 51. In such a case, the pulley 69 of the planetary gear carrier 65 is rotated at a low speed, thus allowing the pulley 69 of the gear carrier 65 to be rotatable at a reduction speed ratio of the pulley 69 to the sun gear 64 of the flywheel 60. The flywheel 60 thus generates a centrifugal force, bringing the brake weight 63 into frictional contact with the brake band 50 and increasing the rotation load of the flywheel 60. Due to such an increase in the flywheel's rotation load, the rotating speed of the gear carrier's pulley 69 is reduced, while the frictional force between each of the three rollers 76 to 78 and the rope 11 is increased. It is thus possible to allow the outside up-down elevator to descend at a low speed.
When there is an obstacle in the moving passage of the outside up-down elevator while the outside up-down elevator descends at such a low speed, the lowering action of the outside up-down elevator may be stopped by removing the external force from the lever 51. When the lever 51 is free from the external force as described above, the brake band 50 is elastically biased by the spring 52, thus being brought into close contact with the outer surface of the flywheel 60 and braking the flywheel 60. The lowering action of the outside up-down elevator is thus stopped.
However, the above safety outside up-down elevator has the following problems.
First, when the lever 51 is operated to release the brake band 50 and lift the outside up-down elevator after the outside up-down elevator is stopped during such a lowering action of the outside up-down elevator, the outside up-down elevator may unexpectedly initially move downward momentarily. That is, the outside up-down elevator in the above state descends a certain distance momentarily from the time the brake band 50 is released to the time a lifting force is given to the outside up-down elevator, thus unexpectedly running against the obstacle in the moving passage and causing a safety hazard.
Second, the brake weight 63 is movably received in the arcuate groove 62 formed on the outer surface of the flywheel's rim 61, thus generating upsetting noises while the outside up-down elevator is transported.
Third, the outside up-down elevator is designed to be moved along a single rope 11 and so it is almost impossible to stably or safely operate the outside up-down elevator. The outside up-down elevator also fails to allow a worker to be effectively balanced thereon or take working instruments. The rope 11 also extends just in front of a worker, thus disturbing the worker while working.